【单选题】

Questions 18 to 20 are based on the following passage.At the end of the passage, you will be given 15 seconds to answer the questions.

Now listen to the passage.
Why would Henning put "weather, whether, wither, and wetter" together in the testA．Because the four words have the same initial "w".
Because the four words have the same ending "er".
C．Because the four words have the similar pronunciation.
D．Because the four words have the similar number of the letters.